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Post by PinkFloyd on Jan 15, 2005 17:03:37 GMT
I received the new WNA headphone PCB's along with the revamped construction manual this morning and things are looking really good! There are two versions of the MKll WNA: PCB1: PCB1 is similar to the previous WNA (and can also be used as a buffer amplifier) except the pcb is a little larger; there are now "two" pairs of output devices per channel to deliver a lot more grunt into low impedance 'phones; the rail splitter is now preceded by a capacitance multiplier to make performance less dependent on the quality of the external power supply so you can now get fantastic performance using a bog standard PSU; the output caps now mount on the pcb; and each channel is now completely independent ( i.e. the amp is dual mono ) so that you can have one power supply per channel. The PCB1 is ideal for people who want to use a stepped attenuator or want to build a fully balanced system using 2 boards... It can also be used as a Dual Class A Buffer Amplifer. PCB2: PCB2 is the same as PCB1 except that the potentiometer and headphone jack now mount on the pcb which is really handy and saves a lot of unnecessary wiring. The component count on MKll has increased also, 12 x transistors (instead of 6) 6 x constant current diodes (instead of 2) 9 x 100uF decoupling caps (instead of 2) and a ferrite bead replaces the R4 jumper. David says the amp now draws 200mA instead of 100mA. The bandwith of the MKll is in excess of 400kHz !! Dimensions: Original: 74 x 105mm PCB1: 90 x 105mm PCB2: 90 x 129mm I've placed a few components onto the PCB2 just to give you an idea of the new layout: I really can't wait to get the WNA MKll up and running it looks very good indeed all that extra decoupling and added grunt should improve on the original WNA by quite some margin. David reckons there is a noticeable improvement to his ears and I've got a feeling, just by looking at the PCB, that my ears will be in for a real sonic treat too ;D looking good!! Mike. EDIT: meant to add, the LM6171 is no longer considered a "tweak" the new amp is based around the LM6171 as standard ;D
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Post by rod on Jan 15, 2005 18:01:39 GMT
Mike, you're quick! I have just finished the mkI, and think that the PCB 2 would have saved me a lot of hassle with wiring. However, it was fun (eventually) and I learned a few things, so I am happy as it stands.
Looking forward to your views on these two variants, I'm sure that won't be long. ;D
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Post by PinkFloyd on Jan 19, 2005 20:34:42 GMT
Mike, you're quick! I have just finished the mkI, and think that the PCB 2 would have saved me a lot of hassle with wiring. However, it was fun (eventually) and I learned a few things, so I am happy as it stands. Looking forward to your views on these two variants, I'm sure that won't be long. ;D Hi Rod, I populated most of the MKll this evening and now only have to fit the BD140 transistors when they arrive (hopefully tomorrow) The build was a piece of cake and it was great being able to solder the ALPS pot directly onto the board without having to faff about with all that wire ;D The amp can either be powered by a single PSU or by 1 PSU per channel so there's a bit of wiring to be done if you're powering the amp from a single PSU through the rail splitter.... basically you connect the output of the rail splitter to power inputs for the left and right channel.... no big deal but "wire" is needed if you are using a single PSU. I hope to finish the amp tomorrow evening (dependant on the trannies and enclosure arriving) and will post some pics of the populated board and also the completed amp ;D Can't wait to have a listen it certainly "looks" the dogs bollocks. All the best. Mike.
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Post by rod on Jan 19, 2005 22:25:09 GMT
Nice one Mike!
Two PSUs eh? Interesting.
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Post by PinkFloyd on Jan 23, 2005 19:50:32 GMT
I populated the PCB a few days ago and here's what she looks like: It took about an hour and a half to put it together and it's now a lot easier with the potentiometer mounting directly onto the PCB Certainly a lot less wire floating about on the PCB which makes for a very tidy job indeed. The output of the rail splitter power supply is not connected to the power inputs of each amplifier channel (in case you want to bypass the rail splitter and use one PSU per channel) so it's necessary to connect the power from the rail splitter to each channel using hookup wire.... even then it's only a small run of wire and can be done either on top of the PCB or underneath if you want to conceal it. You also have to connect the left and right signal outputs on the PCB to the pads next to the headphone socket but, again, this can be done under the board to keep things tidy: All in all the MKll is extremely easy to put together thanks to a very easy to follow construction manual, you wouldn't believe the MKll has 30 more components than the MKl when you look at them side by side.. the MKll is just a lot tidier without all the wire kicking about: MK1 to the left, MKll on the right. A few close up under the bonnet pics. The components I have used are not what WNA supply with the kits... they supply Welwyn RC55Y resistors and Polypropylene capacitors...... I've just used bog standard Metal film resistors and polyester caps but if the amp sounds great I'll whip them out and fit better parts: Close up of the LM6171, Non polar output cap and incandescent lamp current limiter (protects the amp in the event of a short circuit) Provision for a LED power source and resistor on the rail splitter. The rail splitter circuit. Part of the amp circuit. Another view. Just a few notes on the build: 1:I had to wire the headphone jack up as the one I had was too small to reach the edge of the board if surface mounted, the one David supplies is a perfect fit apparantly so that may be something worth noting. It's actually not a bad thing wiring the head-socket as it gives you a bit of play if you've drilled the hole slightly off centre: 2: No problems at all with the 90mm board fitting into a 100mm enclosure, I slotted one side of the PCB into the slots on the hammond, fixed the board to the enclosure using one chrome standoff and secured the front of the board with the potentiometer fixing nut..... it's as solid as a rock: 3: everything went together like a dream and the fact there are no bundles of wire to contend with make it a relatively easy amp to build, even for the novice.... just plug the components in, hook the power and signal up and you're away. After allowing the MKll to energise for an hour I did a very brief comparison between it and the MKl and it's pretty obvious that the MKll displays the same sonic signature as the MKl but the MKll takes things a stage further by adding to the Mkl's good points whilst, at the same time, refining the overall presentation. It's Way to early for me to compare the two in depth but I'll highlight a few points that are very noticeable at this early stage. Bass: This is one area where the MKll clearly improves on the MKl. I thought the MKl's bass was pacey, tuneful and tight but the MKll is something else entirely..... it presents the same tight and tuneful bass but in a more immediate, impactful, refined and 3 dimensional way.... you can home in on bass guitar and seperate it from the rest of the mix no problems at all.... it's just the way the MKl presented it but with bags more clarity, bags more room between the other instruments (if you concentrate you can detach the bassist from the rest of the band) It's proportional to the rest of the frequencies and doesn't overwhelm or underwhelm..... the most natural, enjoyable and musical Bass I have heard through a pair of headphones for sure. Midrange: Very hard to differentiate between MKl and MKll.... MKll brings out the same level of minutiae / microscopic level of detail as MKl but MKll provides more clarity and it's a lot easier to define what is happening...... look at the MKl as wearing a pair of supermarket reading glasses and MKll as wearing a pair of prescription glasses....... sure you can read the same page with both but the MKll definitely makes it easier to read the small print. The same message is there but the MKll makes it easier to understand. Treble: No contest, MKll is slightly better than MKl in this department. MKl has a tendancy to "screech" on certain passages of music (violin springs to mind) the instances where MKl fails in the treble department are few and far between but violin IMO is one of them, it just doesn't sound natural and has a tendancy to sound edgy and shrill. MKll excels in the HF range and violins sound soooo REAL you could almost taste the rosin flying off Stephan Grappeli's bow....... it that good........ I'm listening to Martin Taylor "spirit of Django years apart" as I type this and Stephan's violin has never before sounded "so" real....... absolutely first class. Overall: so far so "very" good, I've only been listening for a couple of hours but, already, I think I can safely say that Dr. White's latest MKll headphone amplifier is a worthwile improvement over the MKl, it's not "incredibly" different sonically but it improves on the MKl by 25%.......... that's my opinion at this early stage, I'll report back after the final fit and finish. NOTE: I populated my MKll with cheap and cheerful parts and compared it to a MKl with top notch parts.. I'm satisfied the mkll is 100% operational so will populate it with the same type of High quality parts the MKl has on board. Finally managed to get the amp fully completed yesterday and fitted an On / Off switch, a Blue LED and fitted heatsinks onto the transistors: The provision on the rail splitter for powering the LED along with the board mounted 4k7 resistor connected in series with the anode leg is very handy indeed and saves soldering a resistor onto the anode leg of the LED. I've noticed the MKll runs warmer than the MKl but that's to be expected as there are double the amount of transistors under the bonnet... The case gets nice and warm after a while (not hot but lukewarm) and the amp seems to sound better once it warms up (about 30 minutes) Sound Quality: LIstening very closely to the MKl & MKll the differences are not as pronounced as I first thought, this may be due to the MKll burning in so I'll give it a good while before doing any serious comparisons. I played a track I know very well (Yello "ocean club") over and over again and listened to it on the MKl and then the MKll switching back and forth for a good hour. It is honestly VERY hard to seperate the two amps at this early stage and any differences between the two are very subtle....... I believe the MKll has a touch more clarity (probably down to the extra decoupling) but on the whole it would take a very well trained ear to notice any differences between the two. Only after prolonged listening (weeks) will I be able to tell if the MKll has any surprises up it's sleeve.... Comparing the two amps side by side (especially two amps with same sonic signature from the same stable) and switching between them listening to the same track is not ideal and can lead to madness The only way I'll know if this amp has more to offer than the MKl is by living with it and listening to it... that's the way it goes with me, I'll be listening to a recording and hear something I've never heard from a recording before (could be a bell, a sneeze, a triangle, a musician scratching his head, whatever) as soon as that happens I know I'm onto a winner and I end up dragging out my entire CD collection and usually find something new in every recording... these are "rare" moments but when they happen you know you're onto something special.
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Post by rod on Jan 29, 2005 18:13:34 GMT
Mike, how's it cooking?
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Post by PinkFloyd on Jan 29, 2005 20:00:45 GMT
Hi Rod, I haven't been able to listen the past week as I haven't been too great. I've never had a headache in my life but, since last Saturday, I've had the most severe pain behind my left eye.... one whole week of it now My Doctor sent me to the Hospital yesterday and my eye was fully checked out and appeared ok, the consultant reckoned it's either "shingles" or "cluster headache" apparantly if a rash appears on my head in the next few days it's shingles and if no rash appears he's pretty sure it's a cluster headache which can apparantly last for 4 to 8 weeks Just my luck, never had a headache in my life and my first headache turns out to be some weird thing lasting days / weeks I've been pumping some serious doses of codeine into me and sleeping most of the time so listening to headphones was the last thing I felt like doing.... on top of this got a phone call this morning informing me that my cousin died last night aged 47 so looks like I'll be out of the scene for a few days re: the headamp....it's been connected to a tuner for a few hundred hours now and I'll report on how it sounds as soon as this bloody freak headache thing subsides. All the best. Mike.
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Alick
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Post by Alick on Jan 29, 2005 22:07:44 GMT
That's a lot of bad news Mike. Glad you've been to the doctor. WTF is a "cluster headache".? That's a new one to me and sounds a bit scary. Sorry about your cousin also. That's a bit scary too; I'll be 47 this year. Hope your luck and health starts to improve soon. EDIT: I should really contribute something on-topic. I've got the case and all the components ready waiting for the Mk2 PCB which I should get from David next week. Build starts soon.
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Post by PinkFloyd on Jan 29, 2005 22:45:19 GMT
A cluster headache www.clusterheadaches.com/ is basically 4 or 5 (or six or seven.....) per day which can go on for weeks..... I'm getting my head scanned on Wednesday just to be sure there's nothing serious going down under the bonnet. I've had my fair share of toothache but this is something else and I just can't function at all with this pain in the head. The Codeine is masking the pain but the minute it wears off "bam" it's back again....... it's like someone drilling into your eyeball from the back of your skull...... I don't lay down easily but I haven't managed to get out of bed this past week...... I'm ok at the moment but am just waiting for the next bout of pain to kick in...... As I say, I've never had a "headache" in my life and maybe this is what a headache feels like? Seems to be lasting a bloody long time tho
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Alick
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Posts: 41
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Post by Alick on Jan 30, 2005 0:45:46 GMT
Doesn't sound like any headache I've ever had (mind, most of mine are whisky-induced). I hope the scan goes well.
BTW, I can't count. I'm only 46 this year.
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Post by rod on Jan 30, 2005 9:26:11 GMT
Mike
I wish you well. I certainly haven't suffered like you are at the moment, although I did have a headache that I ended up in hospital with - still no idea what caused it. They had a look inside my head, but I don't think they found anything (not even a brain!).
Good luck
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Post by GoRedwings19 on Feb 2, 2005 4:11:13 GMT
Hi Mike, I hope you get well soon. Kindest Regards Mike
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Alick
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The Fife Panther strikes again!
Posts: 41
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Post by Alick on Feb 19, 2005 18:52:54 GMT
Well. the progress on my Mk2 has been a little slower than I'd have liked. I started to populate the PCB last weekend but family and domestic obligations, coupled with a sudden desire to use LM6181s (which I didn't have) halted progress until today. The LM6181s and required resistors for the op-amp change arrived in the post this morning (thanks David!) so I intended to complete at least the PCB and hopefully the whole amp. Well, I got the PCB finished, but a knock at the door turned out to be a friend from Inverness who I hadn't seen for a year, so that kyboshed any further progress. I'll try again tomorrow. Anyway, the PCB is as well made and easy to populate as the original Mk1 (that's very easy), although getting a satisfactory result hooking up wires between the rail-splitter and the PSU inputs for the amplifier channels took a few attempts until I was happy. It would have been easier had I bought enough pin headers to cover this requirement, but I'm a cheapskate and didn't. To prove my progess, here are a couple of quick (read poorly taken) photo's showing the populated board and the PSU earth hook-up wires tacked to the underside of the PCB. More progress will be reported when I make any. (Please note that the PCB hasn't been cleaned yet).
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Post by durhamUK on Feb 26, 2005 15:01:51 GMT
Hello all!
So were can i get the kit from and what cost is it...i've tried a few google searchs but not muc luck.
After something to drive my HD580's
Regards
Stottie
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Post by rod on Feb 26, 2005 15:54:25 GMT
Hi Stottie Check out www.wnaudio.com/This David White's "White Noise Audio" site. He's based in Glasgow, and all of his kits are to be found here. Although I would recommend giving him a call to determine exactly which form of kit you want (pcb / complete kit / pcb 1 or 2 / etc.) As such, I don't know what the latest cost is. I bought the previous version of the "complete kit" (previous pcb, that is) in December for £150. This includes absolutely everything other than tools, etc. Like a lot of other builders, I bought a Hammond case for it, as the kit supplied case is a bit basic, although it does the job. I'm really just a beginner, although there are some knowledgeable chaps on here, not least Pink Floyd himself. I'm sure if you have more questions, they will be happy to help out. Cheers, and good luck!
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Alick
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Posts: 41
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Post by Alick on Feb 26, 2005 19:40:39 GMT
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Post by rod on Feb 26, 2005 20:02:30 GMT
Looking good Alick. ;D Nice and neat. Did you find it easier with the pot and socket on the pcb? Certainly looks tidier inside. I'm sure you will have plenty of enjoyment ahead.
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Alick
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Posts: 41
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Post by Alick on Feb 26, 2005 21:01:10 GMT
Thanks Rod; the Mk2 comes in two versions. The PCB Mike built has the pot and headphone socket mounted on the PCB. I chose to build the other version which is smaller and has these components mounted off the board. I think I prefer things that way as it allows more flexibility (and requires less precision) when drilling the front panel.
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Post by rod on Feb 27, 2005 0:41:23 GMT
Ha-ha! Alick, you have made such a tidy job of it, that I overlooked the pot pins and presumed it to be an onboard pcb! I guess your version will make drilling the front plate easier.
...dons dunce's cap and stands in the corner...
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Post by durhamUK on Feb 27, 2005 7:43:25 GMT
Hi Do you receive a PSU with the kit? Also from the posts I may need a better case?
Does anyone know what this compares with the JLH design?
Regards
Stottie
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Post by rod on Feb 27, 2005 10:12:24 GMT
The complete kit comes with a wall wart psu. Most folks consider this to be sufficient for the purpose. As far as the case goes, it's a matter of taste, the supplied case is ok. I think Pink Floyd may have photos of it on his original H**d-F*WNA Head-Amp thread. I haven't compared it with anything else, so somebody may be able to help.
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FritzS
Been here a while!
Sound of Blue Danube
Sound of Blue Danube
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Post by FritzS on Feb 27, 2005 10:52:25 GMT
Dear All - I am new here I have an Sennheiser HD600 and search for an headphone amp - my choice Jan Meier CORDA HA-1 MkII, PPA v2, or some other from HeadWize - and now WNA MKll Gives there anywhere a schema from WNA MKll? I cannot found it. A stock of some OP's I have. I will make the amp self, but I search for a done PCB What is the sound-difference between LM6171 and LM6181? Is there a cap and a lamp in the output signal path?
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Alick
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Post by Alick on Feb 27, 2005 11:36:25 GMT
I don't think that the WNA schematic is posted anywhere on the internet. David White (the White in White Noise Audio) supplies the scematic, parts list and full building instructions with both the full kit and the bare PCB (which he sells for £30 or £35, depending on whether you want on-board pot and jack socket or not).
I haven't listened to the Mk2 with LM6171s yet (but I will, they are sitting on my desk waiting) but Mike has posted his thoughts earlier in this thread and on the WNA MkII thread in Head Fi and seems to marginally prefer the LM6181 sound. All I can say right now is that the Mk2 with the LM6181 is superb.
There are DC blocking capacitors at the input and the output plus a current limiting lamp in the output path. I was concerned about this aspect of the design when I built the Mk1 but those concerns evaporated when I heard the amp. The input capacitor can be dispensed with if the source you are using allows (I did this in my Mk1 with no ill effects). David and Mike have done a lot of work optimising and testing the circuit to allow for the removal of the output capacitor , but they report no sonic benefit. Therefore it can be done, but will allow a potentially (no pun intended) damaging DC voltage through to your headphones if a fault condition develops. The current limiting lamp is there to protect the amplifier in case of a short circuit in your headphone cable. Again, it can be left out and replaced with a wire link, but that's effectively what the lamp is in this circuit anyway.
Summarising, the capacitors and lamp can be omitted if you wish, but there may be little or no benefit in doing so.
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FritzS
Been here a while!
Sound of Blue Danube
Sound of Blue Danube
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Post by FritzS on Feb 27, 2005 12:13:03 GMT
I haven't listened to the Mk2 with LM6171s yet (but I will, they are sitting on my desk waiting) but Mike has posted his thoughts earlier in this thread and on the WNA MkII thread in Head Fi and seems to marginally prefer the LM6181 sound. All I can say right now is that the Mk2 with the LM6181 is superb. I am confused LM6171 is an OP - LM6181 is a current feedback 100 mA driver. LM6181 in place of LM6171?
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Alick
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The Fife Panther strikes again!
Posts: 41
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Post by Alick on Feb 27, 2005 14:32:55 GMT
They are both op-amps. The 6171 is a voltage feedback device and the 6181 is a current feedback version, but they work interchangeably in this application.
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